Renovering af byggeri giver størst bæredygtighed. Foto: Tove Lading.

Building renovation produces greatest sustainability

tirsdag 28 sep 21

Kontakt

Tove Lading
Lektor
DTU Byg
45 25 17 38

Kontakt

Morten Ryberg
Adjunkt
DTU Management
45 25 16 36

Life cycle assessment of four buildings

A lifecycle assessment of four building types in Greenland shows potential for greater sustainability when renovating existing buildings made of concrete.

According to a lifecycle assessment (LCA) of four building types in Greenland published in the journal Building and Environment, renovating existing concrete buildings in Greenland is the most sustainable solution. The assessment shows that renovation in which the load-bearing structure is recycled is more sustainable than new builds, regardless of building type. The researchers have compared renovation with three different types of new builds: a structure made of concrete and inorganic building materials, a mixed structure with concrete and wood, and a 100 per cent wood structure in CLT.

Renovation shows the best performance on all environmental parameters in the LCA, where, for example, the researchers have assessed aspects such as carbon emissions, energy consumption, transportation of building materials, potential for renewal, and harmful impacts on the environment.

"It’s generally an important sustainability parameter to renovate rather than construct new buildings, regardless of whether this is in Greenland, in Denmark, or in many other places in the world"
Tove Lading, associate professor.

There is a great wish in Greenland to increase consumption of local building materials at the expense of imported materials. However, Greenland has few resources that are suitable for construction. Concrete has been regarded as the most local building material due to its high contents of stone and gravel. If you look at the total amount of imported materials for a building project and their environmental impact, there are, however, no environmental benefits from new builds made of concrete. The life cycle assessment shows that transportation of building materials means relatively little in the accounts, even though virtually all materials in Greenland are imported from Denmark. 

“Instead, we must regard already imported materials as local and recycle them to the greatest possible extent. The most obvious solution is to recycle concrete structures, thus reducing the need for new cement. Precisely the production of cement is a major factor in the carbon emissions of the building sector,” says Associate Professor Tove Lading from DTU Civil Engineering, who carried out the analysis, together with Assistant Professor Morten Ryberg from DTU Management.

The LCA is particularly relevant in Greenland, where a large number of residential, administrative, and institutional buildings are dilapidated and are facing either demolition or renovation. The findings of the assessment go against the current practice in Greenland, where dilapidated buildings are generally demolished and replaced with new builds.

However, the conclusions drawn in the analysis have general validity and are not limited to the building sector in Greenland.

“As transportation is of relatively little significance in the overall picture, the point is probably also applicable elsewhere. It’s generally an important sustainability parameter to renovate rather than construct new buildings, regardless of whether this is in Greenland, in Denmark, or in many other places in the world,” says Tove Lading.